[PD] derivative function

[Mathieu Bouchard]

On Mon, 26 Jun 2006, Federico wrote:

> is there an object to compute the derivative function of a signal?
> f(x)=x      => f'(x)=1

[rzero~ 1] times a constant.

> and a more question: has this anything to do with complex signals or
> fourier?

Fourier(f')(w) = i*w*Fourier(f)(w)

so in the frequency domain, a derivative can be achieved by multiplying 
the spectrum by an imaginary [phasor~] tuned to fit the blocksize, times 
another constant.

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| Mathieu Bouchard - tél:+1.514.383.3801 - http://artengine.ca/matju
| Freelance Digital Arts Engineer, Montréal QC Canada